Definition of Meningitis - gram-negative:

Gram-negative meningitis is an infection of the membranes covering the brain and spinal cord (meninges) caused by gram-negative bacteria (bacteria that turn pink when exposed to a special stain).

Causes, incidence, and risk factors:

Acute bacterial meningitis, which can be caused by gram-negative bacteria, is very serious and should be treated immediately to prevent permanent damage. Bacteria causing gram-negative meningitis include Pseudomonas aeruginosa, Escherichia coli, Enterobacter aerogenes, Proteus morganii, and Klebsiella pneumoniae.

Gram-negative meningitis is much more common in infants than adults.

Risk factors in adults and children include recent brain surgery and recent injury to the head. The infection is sometimes connected to spinal fluid shunt placement after brain surgery. Spinal abnormalities, urinary tract abnormalities, a local infection, or urinary tract infection may make children vulnerable to this type of meningitis.